Inhalation of hydrogen gas reduces liver injury during major hepatotectomy in swine

A "philosophical molecule," hydrogen may overcome senescence and intractable diseases

It has been revealed that the cause of senescence and diseases is associated with the reactive oxygen species “hydroxyl radicals” (·OH). Senescence and diseases may be overcome as long as we can scavenge •OH mostly produced in mitochondria. It is one and only one “molecular hydrogen” (H₂) that can both penetrate into the mitochondria and scavenge the •OH. The H₂ in the body can function in disease prevention and recovery. H₂ gas is explosive so that a safe hydrogen inhaler has to be developed for home use. We would like to advocate the great use of H₂.

Hydrogen treatment: a novel option in liver diseases

Hydrogen therapy is a very promising treatment against several diseases due to its mild attributes, high affinity and inherent biosafety. However, there is little elaboration about current hydrogen treatment in liver diseases. This article introduces the administration of hydrogen and mechanisms of hydrogen therapy in vivo, including modulating reactive oxygen species, apoptosis and autophagy, and inflammation, affecting mitochondria, as well as protein transporters. The major focus is clinical hydrogen use and related mechanisms in liver dysfunction or diseases, including non-alcoholic fatty liver disease, hepatitis B, liver dysfunction caused by liver tumour and colorectal tumour chemotherapy. Further, the article reveals ex vivo hydrogen application in liver protection. Finally, the article discusses the current and future challenges of hydrogen therapy in liver diseases, aiming to improve knowledge of hydrogen therapy and provide some insights into this burgeoning field.

Hydrogen: An Endogenous Regulator of Liver Homeostasis

Basic and clinical studies have shown that hydrogen (H₂), the lightest gas in the air, has significant biological effects of anti-oxidation, anti-inflammation, and anti-apoptosis. The mammalian cells have no abilities to produce H₂ due to lack of the expression of hydrogenase. The endogenous H₂ in human body is mainly produced by anaerobic bacteria, such as Firmicutes and Bacteroides, in gut and other organs through the reversible oxidation reaction of 2 H⁺ + 2 e^- ⇌ H₂. Supplement of exogenous H₂ can improve many kinds of liver injuries, modulate glucose and lipids metabolism in animal models or in human beings. Moreover, hepatic glycogen has strong ability to accumulate H₂, thus, among the organs examined, liver has the highest concentration of H₂ after supplement of exogenous H₂ by various strategies in vivo. The inadequate production of endogenous H₂ play essential roles in brain, heart, and liver disorders, while enhanced endogenous H₂ production may improve hepatitis, hepatic ischemia and reperfusion injury, liver regeneration, and hepatic steatosis. Therefore, the endogenous H₂ may play essential roles in maintaining liver homeostasis.

Inhalation of molecular hydrogen prevents ischemia-reperfusion liver damage during major liver resection

Background

Liver resection is a surgical procedure associated with a high risk of hepatic failure that can be fatal. One of the key mechanisms involves ischemia-reperfusion damage. Building on the well-known positive effects of hydrogen at mitigating this damage, the goal of this work was to demonstrate the antioxidant, anti-inflammatory, and anti-apoptotic effects of inhaled hydrogen in domestic pigs during major liver resection.

Methods

The study used a total of 12 domestic pigs, 6 animals underwent resection with inhaled hydrogen during general anesthesia, and 6 animals underwent the same procedure using conventional, unsupplemented, general anesthesia. Intraoperative preparation of the left branch of the hepatic portal vein and the left hepatic artery was performed, and a tourniquet was applied. Warm ischemia was induced for 120 minutes and then followed by liver reperfusion for another 120 minutes. Samples from the ischemic and non-ischemic halves of the liver were then removed for histological and biochemical examinations.

Results

An evaluation of histological changes was based on a numerical expression of damage based on the Suzuki score. Liver samples in the group with inhaled hydrogen showed a statistically significant reduction in histological changes compared to the control group. Biochemical test scores showed no statistically significant difference in hepatic transaminases, alkaline phosphatase (ALP), lactate dehydrogenase (LD), and lactate. However, a surprising result was a statistically significant difference in gamma-glutamyl-transferase (GMT). Marker levels of oxidative damage varied noticeably in plasma samples.

Conclusions

In this experimental study, we showed that inhaled hydrogen during major liver resection unquestionably reduced the level of oxidative stress associated with ischemia-reperfusion damage. We confirmed this phenomenon both histologically and by direct measurement of oxidative stress in the organism.

Hydrogen gas distribution in organs after inhalation: Real-time monitoring of tissue hydrogen concentration in rat

Hydrogen has therapeutic and preventive effects against various diseases. Although animal and clinical studies have reported promising results, hydrogen distribution in organs after administration remains unclear. Herein, the sequential changes in hydrogen concentration in tissues over time were monitored using a highly sensitive glass microsensor and continuous inhalation of 3% hydrogen gas. The hydrogen concentration was measured in the brain, liver, kidney, mesentery fat and thigh muscle of rats. The maximum concentration, time to saturation, and other measurements representing the dynamics of distribution were obtained from the concentration curves, and the results obtained for different organs were compared. The time to saturation was significantly longer (20.2 vs 6.3-9.4 min. P = 0.004 in all cases) and increased more gradually in muscle than in the other organs. The maximum concentration was the highest in liver and the lowest in the kidney (29.0 ± 2.6 vs 18.0 ± 2.2 μmol/L; P = 0.03 in all cases). The concentration varied significantly depending on the organ (P = 0.03). These results provide the fundamentals for elucidating the mechanisms underlying the in vivo favourable effects of hydrogen gas in mammalian systems.

Subcutaneous injection of hydrogen gas is a novel effective treatment for type 2 diabetes

Aims/Introduction

In previous studies, hydrogen gas (H₂₎ administration has clearly shown effectiveness in inhibiting diabetes. Here, we evaluated whether subcutaneous injection of H₂ shows enhanced efficacy against type 2 diabetes mellitus induced in mice by a high‐fat diet and low‐dose streptozotocin treatment.

Material and Methods

H₂ was injected subcutaneously at a dose of 1 mL/mouse/week for 4 weeks. Type 2 diabetes mellitus‐associated parameters were then evaluated to determine the effectiveness of subcutaneous H₂ administration.

Results

The bodyweight of H₂‐treated mice did not change over the course of the experiment. Compared with the untreated control animals, glucose, insulin, low‐density lipoprotein and triglyceride levels in the serum were significantly lower in treated mice, whereas high‐density lipoprotein cholesterol in the serum was significantly higher. Glucose tolerance and insulin sensitivity were both improved in H₂‐treated mice. Diabetic nephropathy analysis showed significant reductions in urine volume, urinary total protein and β2‐microglobulin, kidney/bodyweight ratio, and kidney fibrosis associated with subcutaneous injection of H₂.

Conclusions

Subcutaneous injection of H₂ significantly improves type 2 diabetes mellitus and diabetic nephropathy‐related outcomes in a mouse model, supporting further consideration of subcutaneous injection as a novel and effective route of clinical H₂ administration.

Impact of splenic artery ligation after major hepatectomy on liver function, regeneration and viability

It was reported that prevention of acute portal overpressure in small-for-size livers by inflow modulation results in a better postoperative outcome. The aim is to investigate the impact of portal blood flow reduction by splenic artery ligation after major hepatectomy in a murine model. Forty-eight rats were subjected to an 85% hepatectomy or 85% hepatectomy and splenic artery ligation. Both groups were evaluated at 24, 48, 72 and 120 post-operative hours: liver function, regeneration and viability. All methods and experiments were carried out in accordance with Coimbra University guidelines. Splenic artery ligation produces viability increase after 24 h, induces a relative decrease in oxidative stress during the first 48 hours, allows antioxidant capacity increment after 24 h, which is reflected in a decrease of half-time normalized liver curve at 48 h and at 72 h and in an increase of mitotic index between 48 h and 72 h. Splenic artery ligation combined with 85% hepatectomy in a murine model, allows portal inflow modulation, promoting an increase in hepatocellular viability and regeneration, without impairing the function, probably by inducing a less marked elevation of oxidative stress at first 48 hours.

Beneficial biological effects and the underlying mechanisms of molecular hydrogen - comprehensive review of 321 original articles

Therapeutic effects of molecular hydrogen for a wide range of disease models and human diseases have been investigated since 2007. A total of 321 original articles have been published from 2007 to June 2015. Most studies have been conducted in Japan, China, and the USA. About three-quarters of the articles show the effects in mice and rats. The number of clinical trials is increasing every year. In most diseases, the effect of hydrogen has been reported with hydrogen water or hydrogen gas, which was followed by confirmation of the effect with hydrogen-rich saline. Hydrogen water is mostly given ad libitum. Hydrogen gas of less than 4 % is given by inhalation. The effects have been reported in essentially all organs covering 31 disease categories that can be subdivided into 166 disease models, human diseases, treatment-associated pathologies, and pathophysiological conditions of plants with a predominance of oxidative stress-mediated diseases and inflammatory diseases. Specific extinctions of hydroxyl radical and peroxynitrite were initially presented, but the radical-scavenging effect of hydrogen cannot be held solely accountable for its drastic effects. We and others have shown that the effects can be mediated by modulating activities and expressions of various molecules such as Lyn, ERK, p38, JNK, ASK1, Akt, GTP-Rac1, iNOS, Nox1, NF-κB p65, IκBα, STAT3, NFATc1, c-Fos, and ghrelin. Master regulator(s) that drive these modifications, however, remain to be elucidated and are currently being extensively investigated.

Effect of hydrogen injected subcutaneously on testicular tissues of rats exposed to cigarette smoke

Smoking is one of the most common reasons inducing reactive oxygen species in semen. High concentration of active oxygen will cause decrease of sperm density and viability and induce oxidative injury of sperm DNA which has become the hot spot in male infertility. Although hydrogen was found to be an effective remover of active oxygen in liver, heart, kidney and brain, the same effect has not been discussed in reproductive system. The aim of this study was to investigate the protective effect of hydrogen against cigarette smoke-induced damage in rat reproductive system. Adult male Wistar rats were randomly divided into four groups to conduct this experiment, results showed that rats in SK+HSI group (passive smoking and hydrogen subcutaneous injection group) exhibited larger amount of sperm count, smaller sperm deformation rate, higher levels of testosterone and SOD in serum and testis, lower levels of MDA in testis and less morphologic abnormalities compared to SK+NSI group (passive smoking and nitrogen subcutaneous injection group). As a consequence, we concluded that injected subcutaneously exerted protective effects on reproductive system injury of male rats exposed to cigarette smoke through inhibiting oxidative damage.

Estimation of the hydrogen concentration in rat tissue using an airtight tube following the administration of hydrogen via various routes

Hydrogen exerts beneficial effects in disease animal models of ischemia-reperfusion injury as well as inflammatory and neurological disease. Additionally, molecular hydrogen is useful for various novel medical and therapeutic applications in the clinical setting. In the present study, the hydrogen concentration in rat blood and tissue was estimated. Wistar rats were orally administered hydrogen super-rich water (HSRW), intraperitoneal and intravenous administration of hydrogen super-rich saline (HSRS), and inhalation of hydrogen gas. A new method for determining the hydrogen concentration was then applied using high-quality sensor gas chromatography, after which the specimen was prepared via tissue homogenization in airtight tubes. This method allowed for the sensitive and stable determination of the hydrogen concentration. The hydrogen concentration reached a peak at 5 minutes after oral and intraperitoneal administration, compared to 1 minute after intravenous administration. Following inhalation of hydrogen gas, the hydrogen concentration was found to be significantly increased at 30 minutes and maintained the same level thereafter. These results demonstrate that accurately determining the hydrogen concentration in rat blood and organ tissue is very useful and important for the application of various novel medical and therapeutic therapies using molecular hydrogen.

Hydrogen gas presents a promising therapeutic strategy for sepsis

Sepsis is characterized by a severe inflammatory response to infection. It remains a major cause of morbidity and mortality in critically ill patients despite developments in monitoring devices, diagnostic tools, and new therapeutic options. Recently, some studies have found that molecular hydrogen is a new therapeutic gas. Our studies have found that hydrogen gas can improve the survival and organ damage in mice and rats with cecal ligation and puncture, zymosan, and lipopolysaccharide-induced sepsis. The mechanisms are associated with the regulation of oxidative stress, inflammatory response, and apoptosis, which might be through NF- κ B and Nrf2/HO-1 signaling pathway. In this paper, we summarized the progress of hydrogen treatment in sepsis.

The role of anesthetic drugs in liver apoptosis

CONTEXT

The modern practice of anesthesia is highly dependent ona group of anesthetic drugs which many of them are metabolized in the liver.

EVIDENCE ACQUISITION

The liver, of course, usually tolerates this burden. However, this is not always an unbroken rule. Anesthetic induced apoptosis has gained great concern during the last years; especially considering the neurologic system.

RESULTS

However, we have evidence that there is some concern regarding their effects on the liver cells. Fortunately not all the anesthetics are blamed and even some could be used safely, based on the available evidence.

CONCLUSIONS

Besides, there are some novel agents, yet under research, which could affect the future of anesthetic agents' fate regarding their hepatic effects.